Irish authorities are liaising with Polish officials over the source of the contamination.
Traces were found at Rangeland Foods in Co Monaghan, owned by ABP Food Group.
The Group has lost contracts with:
- Co-Operative Group
- Burger King
More top news
Specially-trained prison security teams have been sent to HMP Hewell near Redditch, after trouble broke out on one of the prison's wings.
Household names are among 40 women to sign open letter to BBC Director General saying he must "act now" to end pay discrimination.
"We've never actually spoken so publicly about her," the Duke of Cambridge said. "But we felt that this was the right time to do it."